Ultra-local model-free speed prediction control based on high-order sliding mode compensation for PMSM drives

Abstract

The model predictive control (MPC) is widely used in permanent magnet synchronous motor (PMSM) motion systems because of its simple structure, easy implementation, and reasonable control effect to realize accurate speed tracking. However, MPC relies on the mathematical model of a PMSM. During motor operation, parameter drifts will occur and the model will be mismatched. Furthermore, motor operation may be affected by known and unknown disturbances, resulting in a degraded control performance. To solve this problem, ultra-local model-free speed prediction control (MFSPC), based on high-order sliding mode compensation (HOSMC), is proposed. Only the output and input of the speed loop are used to establish MFSPC and no system parameters are considered. HOSMC shows good control performance under nonlinearity and is not sensitive to parameter changes and external disturbances, which improves the robustness and anti-interference performance of the control system. Therefore, the current output is composed of two parts: an MFSPC output current and an HOSMC output current. The experimental results show that the method has strong robustness and anti-interference ability, and it can achieve a rapid dynamic response, track rated speed, reduce current and speed ripples, and suppress chattering.